using System;
using System.Collections.Generic;
using System.Text;
using System.Globalization;

using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Validation;
using Microsoft.Practices.EnterpriseLibrary.Validation.Validators;

using EntLibContrib.Validation.Configuration;

namespace EntLibContrib.Validation.Validators
{
    [ConfigurationElementType(typeof(EnumDefinedValidatorData))]
    public class EnumDefinedValidator : ValueValidator
    {
        /// <summary>
        /// <para>Initializes a new instance of the <see cref="EnumDefinedValidator"/>.</para>
        /// </summary>
        public EnumDefinedValidator()
            : this(false)
        { }

        /// <summary>
        /// <para>Initializes a new instance of the <see cref="EnumDefinedValidator"/>.</para>
        /// </summary>
        /// <param name="negated">True if the validator must negate the result of the validation.</param>
        public EnumDefinedValidator(bool negated)
            : this(null, negated)
        { }

        /// <summary>
        /// <para>Initializes a new instance of the <see cref="EnumDefinedValidator"/>.</para>
        /// </summary>
        /// <param name="messageTemplate">The message template to use when logging results.</param>
        public EnumDefinedValidator(Type enumType, string messageTemplate)
            : this(messageTemplate, false)
        { }

        /// <summary>
        /// <para>Initializes a new instance of the <see cref="EnumDefinedValidator"/>.</para>
        /// </summary>
        /// <param name="messageTemplate">The message template to use when logging results.</param>
        /// <param name="negated">True if the validator must negate the result of the validation.</param>
        public EnumDefinedValidator(string messageTemplate, bool negated)
            : base(messageTemplate, null, negated)
        {
        }

        /// <summary>
        /// Implements the validation logic for the receiver.
        /// </summary>
        /// <param name="objectToValidate">The object to validate.</param>
        /// <param name="currentTarget">The object on the behalf of which the validation is performed.</param>
        /// <param name="key">The key that identifies the source of <paramref name="objectToValidate"/>.</param>
        /// <param name="validationResults">The validation results to which the outcome of the validation should be stored.</param>
        protected override void DoValidate(object objectToValidate, object currentTarget, string key, ValidationResults validationResults)
        {
            bool logError = false;
            bool isObjectToValidateNull = objectToValidate == null;

            if (!isObjectToValidateNull)
            {
                logError = !Enum.IsDefined(objectToValidate.GetType(), objectToValidate);
            }

            if (isObjectToValidateNull || (logError != Negated))
            {
                this.LogValidationResult(validationResults,
                    GetMessage(objectToValidate, key),
                    currentTarget,
                    key);
            }
        }

        /// <summary>
        /// Gets the message representing a failed validation.
        /// </summary>
        /// <param name="objectToValidate">The object for which validation was performed.</param>
        /// <param name="key">The key representing the value being validated for <paramref name="objectToValidate"/>.</param>
        /// <returns>The message representing the validation failure.</returns>
        protected override string GetMessage(object objectToValidate, string key)
        {
            return string.Format(CultureInfo.CurrentUICulture,
                this.MessageTemplate,
                objectToValidate,
                key,
                this.Tag,
                objectToValidate.GetType().Name);
        }

        /// <summary>
        /// Gets the Default Message Template when the validator is non negated.
        /// </summary>
        protected override string DefaultNonNegatedMessageTemplate
        {
            get { return Resources.EnumDefinedNonNegatedDefaultMessageTemplate; }
        }

        /// <summary>
        /// Gets the Default Message Template when the validator is negated.
        /// </summary>
        protected override string DefaultNegatedMessageTemplate
        {
            get { return Resources.EnumDefinedNegatedDefaultMessageTemplate; }
        }
    }
}
